10 Things You Should Know About Virtualization

With Citrix's recent XenSource acquisition, a new hypervisor on the way from Microsoft and Oracle now extending its sincere Red Hat flattery to the virtual world, the buzz around server virtualization is louder than ever. Here are 10 things to keep in mind as you consider making the leap to virtualization.

1. Virtually Everything is Virtual

Lately, it seems that every vendor is out to wave the virtualization flag. Cut through the buzz by focusing on functionality. If you get confused, ask your sales reps what their products used to be called before virtual-palooza began.

2. You Can Virtualize Anywhere

Virtualization can pay big dividends on big server iron, but you can build and test your VMs (virtual machines) on practically any system—from a notebook PC on up. A free desktop virtualization app such as VMware Player is a good place to get started.

3. Think About Storage

Virtualization sucks up a great deal of storage. If you're testing out the technology on your notebook, turn to an external hard drive for extra capacity and speed. For production settings, a SAN (storage-area network) is a must-have--you can't conduct live host-to-host migrations without one.

4. Don't Pass on Failover

Consolidating several servers onto one can boost efficiency significantly, but don't allow your high-utilization virtual host to become a single point of failure. Fortunately, failover is a strong suit of most virtualization products.

5. Software Appliances Are Your Friends

A virtualization platform is nothing without some VMs to host. Software appliances such as those available from rPath, VMware and and Microsoft bundle the applications you wish to run with the operating system components these apps require to jump-start your virtual adventures.

6. Mind the Licenses

While virtualization products make it easy to turn a single physical server into a group of virtual servers, these products can't make software licenses magically multiply. It's important to stay on top of license needs as your VM population grows.

7. Not All Vendors Are Virtualization-Friendly

While most of the technology world is going virtual, not all ISVs are ready for a new platform. Make sure your vendor supports its products on your chosen virtualization platform.

8. Shop Around

The biggest name in virtualization right now is VMware, but the field is packed with new entrants. Pick the one whose cost, focus and functionality fit best with your organization.

9. Figure Out Who's Going to Pay

In a one-application-per-server world, it's easier to associate hardware costs with particular departments. Going virtual means devoting more attention to chargebacks within your company.

10. Simplicity Can Be Complicated

Virtualization can enable IT administrators to forget about the hardware and focus on the workloads with which they're charged. For those charged with maintaining the virtual platform itself, however, virtualization does bring added complexity.

理智！虚拟化浪潮下需要清楚的十点

随着思杰（Citrix）收购XenSource，从微软、Oracle到红帽无疑又掀起了一拨虚拟化的高潮，而且比以往任何时候都要有声势。保持头脑清醒，在把握虚拟浪潮之前有十点需要清楚。

1.         事实上一切都是虚拟的

近来很多厂商加入到虚拟中来，各个都标榜自己的功能。如果你为此（指诸多厂商和产品）而困惑，那就去问问销售人员这些产品在虚拟化浪潮到来之前的称呼是什么。

2.         任何地方都可以虚拟化

虚拟化可以给大的服务器带来大的收益，但实际上你可以在任何系统上测试你的虚拟机——笔记本、PC都可以。一个免费的桌面电脑虚拟应用（如VMware Player）就可以让你开始虚拟之路。

3.         记得考虑存储

虚拟化需要大量的存储。如果你在桌面电脑上测试虚拟技术，建议使用外接硬盘驱动以提供更大的容量和更高的速度。至于产品设置，一个SAN（存储区域网络）是必备的，没有它你不可能实现主机到主机的搬迁。

4.         不要忽略故障转移(Failover)

合并多个服务器到一个可以极大地提高效率，但不要让你的高端应用主机（high-utilization host）成为影响成败的唯一节点。庆幸的是，故障转移是大多数虚拟化产品的强力配件。

{注：发生资源故障时，故障转移管理器可能重新启动该资源或将资源及其依存资源脱机。如果将资源脱机，它会指示将该资源的所有权移交给另一节点并且以新节点的名义重新启动该资源。这被称作故障转移。}

5.         软件工具是你的朋友

没有虚拟机来伺服虚拟化产品一无是处。若想软件工具（如rPath、VBware和微软提供的）运行在操作系统组件上，就需要它们来启动你的虚拟化体验。

6.         注意软件许可

虽然虚拟化产品可以使你的一个物理服务器变成一组虚拟的服务器，但却不会让你的软件许可增加，所以在增加虚拟机的同时，不要忘了保证你所需要的软件许可。

7.         并不是所有厂商都真的做虚拟

虽然技术世界已经渐入虚拟化，但并非所有的软件开发商都有这个能力。确保你产品的厂商在你选择虚拟化的时候能够提供你支持。

8.         选择厂商

现在而言虚拟化最响亮的厂商自然是VMware，但这个领域不断有进入者。所以选择一个技术专长和功能符合你企业的厂商。

9.         责任清楚

在一个服务器一个应用的时代，哪个部门负责硬件的花费很好处理；虚拟则意味着硬件的费用要分摊到公司里的不同部门上。

10.     简单却又复杂

虚拟使IT管理员不必记得硬件而只专注于他们所管理的工作上。但对于那些管理虚拟平台的而言，虚拟化却增加了麻烦。